Rotatable link

ABSTRACT

The invention relates to a rotatable link, which may e.g. be incorporated in an upright. The upright may be used e.g. in connection with a support for a card terminal. The rotatable link may be characterized s a rotary friction link. Compressive forces caused by a mechanical tension in a pipe are transferred via two first objects to a second object clamped between them. The two first objects are secured and partly built into the pipe, and the second object is rotatable relative to the pipe. The second object constitutes a rotatable link part on which a plated may be welded to provide an upright.

The invention relates to a rotatable link, e.g. for use in connectionwith a support for a piece of hardware, such as a card terminal.Moreover, the invention relates to a rotatable upright. In addition, theinvention relates to use of a rotatable upright for the mounting thereonof an object, such as a piece of hardware, e.g. a card terminal.

PRIOR ART

Rotatable links, such as ball bearings, are known. A special type ofball bearings has an applied tension between the balls in the link andthe face on which they move during rotation. This applied tensionresults in an increased friction in the movement of the balls, and thelink may be characterized as sluggish in the rotary movement. However,the friction decreases in the use of the link so that the sluggishnessis reduced, and frequent adjustments of the applied tension are requiredto maintain the sluggishness.

OBJECTS OF THE INVENTION

It is an object of the invention to provide a rotatable link whichrequires few post tensionings during the service life of the link.

It is an object of the invention to provide a rotatable link which isinexpensive to manufacture.

It is an object of the invention to provide a rotatable upright having aplate so that the plate may be moved by hand in a rotary movement.

It is an object of the invention to provide a rotatable link for use fora plate on which a piece of hardware, such as a card terminal, may besecured, and the plate is additionally provided with a strap, handle orthe like so that the strap, handle or the like on the plate may begripped by hand, and the plate may be moved in said rotary movementabout the link.

It is an object of the invention to provide a rotatable link which, inaddition to being sufficiently slack to be affected by hand, is alsosuitably tight so that a plate mounted on the rotatable link maintainsits position after forces have been exerted by hand, and even if heavyobjects are mounted on the plate and a moment is thus produced about theaxis of the rotatable link.

It is an object of the invention that the use of the link only givesrise to few post tightenings of the link, even after many repetitions ofthe rotary movement of the link.

It is an object of the invention that an object may be placed on anupright with the object in a first position, and that the object may bebrought to a second position by rotary movements, and that the secondposition is maintained after rotary movements have been performed, andthe object is operated by users who want an individual setting of theposition, such as wheelchair users and non-wheelchair users, where theposition is changed by the two types of users.

Further, it is an object of the invention to be able to incorporate alink having the above-mentioned properties, so that it is presenttransversely to and partially inside a pipe opening so as to bepartially concealed seen from the outside of the pipe.

In addition, it is an object of the invention that the plate must becapable of being rotated by a range of at least about 40° about the axisof the link.

It has been attempted to achieve these objects with the followingrotatable link and rotatable upright.

DESCRIPTION

According to an aspect of the present invention, there is provided arotatable link as defined in claim 1.

The rotatable link may be described as a rotary friction link. Therotary link has a certain sluggishness which is owing to friction in theparts of the link.

In an embodiment, the pipe is a pipe stub which is short measured in thelongitudinal direction relative to the diameter of the pipe. In anembodiment, the pipe is round. The pipe may also be elliptic. The pipemay also be made of metal, such as a steel alloy. The pipe may bedeformed elastically. The thickness of the pipe depends on the materialof the pipe and on the load which the link is to be capable of carryingand rotating. The pipe has two ends which each have a rim. Part of theone rim constitutes contact faces for the first objects. The rim may beshaped so as to form a support for the first objects in order to createcontact along the first object in such as 25% or more of thecircumference of the first object, such as 50% or more of thecircumference of the first object, such as 75% or more of thecircumference of the first object. The remaining part of the one rimconstitutes two rim sections. The rim sections may be configured suchthat they have notches and cut-outs therein. In an embodiment, the onerim section forms part of a plane which forms an angle of 0-40° with thehorizontal, such as 10-30° with the horizontal, and the other rimsection is part of a plane which forms an angle of 40-80° with thehorizontal, such as 50-70° with the horizontal. In an embodiment, a pawlis provided in the interior of the pipe, extending from the interior ofthe pipe wall inwards toward the centre of the pipe.

In an embodiment, the first objects are cylinders. The first objects mayhave two end faces of essentially the same size. In another embodiment,the first objects taper in the longitudinal axis of the object, so thatone end face is smaller than the other end face. In an embodiment, thecontour of the first objects are curved and may have a convex or aconcave contour, while, in another embodiment, the contour isessentially rectilinear.

The first objects may be secured to the pipe edge by welding orsoldering, e.g. TIG-welding, or another form of attachment.

In an embodiment, the second object is a cylinder. In an embodiment, thesecond object is a regular cylinder having a rectilinear contour and endfaces of essentially the same size. In another embodiment, the contourof the object is curved and may be convex or concave. The rims of eachof the end faces of the second object may be formed by e.g. milling sothat the rim has no sharp edges or burrs.

In an embodiment, the attachment means is a screw. The screw fits athread on one of the two first objects. The attachment means has adiameter which allows it to pass through the bores in the objects, andthe diameter is essentially equal to the diameter of the bored hole inthe objects.

In an embodiment, there is one or more points on the contour of thesecond object which are more remote from the axis of the attachmentmeans, measured perpendicularly to the axis of the attachment means,than the distance of points on the contour of each the two first objectsfrom the axis of the attachment means, measured perpendicularly from theaxis of the attachment means.

In an embodiment, the area of an end face of a first object, said endface being the one closest to the second object, is smaller than thearea of the end faces of the second object, for each of the firstobjects.

In an embodiment, the unit is secured with its longitudinal directionperpendicular to the longitudinal direction of the pipe.

By assembling the first objects and the second object with theattachment means into a unit, it is ensured that the objects are kepttogether about a common axis which constitutes the axis of rotation ofthe link.

By providing a unit like the foregoing one and mounting it in a pipe, asimple and inexpensive rotatable link consisting of few components isprovided.

When the mechanical tension in the pipe produces compressive forces fromthe walls of the pipe inwards toward the centre of the pipe, this causesthe link to be sufficiently slack for it to be affected by hand, whilethe link is also sluggish.

In addition, as a result of the mechanical tension in the pipe theattachment means need not be tightened very much in the assembly of theobjects, for the given desired sluggishness. Thus, the attachment meansis not very prone to work loose, resulting in few post tightenings.

A mechanical tension in the pipe may be detected by separating thesecond object from the unit and then measuring the distance between thetwo first objects. If the distance between the two first objects issmaller, when the second object has been separated from the unit, thanthe length of the second object, this indicates that a mechanicaltension was present in the pipe before the second object was separatedfrom the unit. The distance and the length are measured in the directionof the bores.

According to an aspect of the present invention, there is provided arotatable link as stated in claim 2.

An apertured disc is an object with a hole. In an embodiment, theapertured disc is an object having a small thickness relative to thesize of the width of the disc. In an embodiment, the apertured disc isessentially circular.

The use of apertured discs results in a smoother operation of the link,among other things. In an embodiment, use is made of apertured discs toreduce the number of post tightenings of the attachment means in thelink. In an embodiment, the frictional forces in the link areessentially smoothed out in the entire range of rotation of the link bythe use of apertured discs according to claim 2.

The apertured discs may be positioned with their faces in contact withan end face of the second object and an end face of the first object, orin contact with an end face of the second object and a second apertureddisc face, or in contact with an end face of the first object and asecond apertured disc face, or in contact with two different apertureddisc faces. The apertured discs may be of the same size or of differentsizes.

According to an aspect of the present invention, there is provided arotatable link as stated in claim 3.

In an embodiment, four pairs of apertured discs are used in a rotarylink.

According to an aspect of the present invention, there is provided arotatable link as stated in claim 4.

The apertured discs may be of the same material or of differentmaterials.

In an embodiment, the apertured disc is a spring disc.

In an embodiment, there are one pair of apertured discs of one materialand three pairs of apertured discs of another material.

In an embodiment, there are one pair of apertured discs of brass andthree pairs of apertured discs of steel.

According to an aspect of the present invention, there is provided arotatable upright as stated in claim 5.

Thus, there is a provided an upright which, in addition to beingsufficiently slack to be affected by hand, is also suitably tight sothat the plate maintains its position after forces have been exerted byhand, and even if objects are mounted on the plate, and a moment isproduced about the axis of the rotatable link.

The plate may be secured to the rotatable link part by welding. In anembodiment, the plate is secured with a large face to the rotatable linkpart.

According to an aspect of the present invention, there is provided arotatable upright as stated in claim 6.

By providing an upright according to claim 6, forces may readily beapplied by hand to effect a rotary movement of the rotatable link bygripping the handle. The handle may be shaped as a strap or the like.

According to an aspect of the present invention, there is provided arotatable upright as stated in claim 7.

By providing an upright according to claim 7, simple mounting of therotatable upright on a rod may be achieved.

The rod has an outside diameter which is approximately equal to andsmaller than the inside diameter of the pipe. The pipe may be mounted onother objects, such as other rods in extension of the rod in one and thesame direction measured along the longitudinal directions of the rod andthe object.

In an embodiment, the rotatable upright may perform a rotary movement ofthe pipe about the rod. Hereby, a rotatable upright is achieved whichhas two rotary axes that are essentially perpendicular to each other.

According to an aspect of the present invention, there is provided a useas stated in claim 8.

A use according to claim 8 ensures that an object may be placed on anupright with the object in a first position, and that the object may bebrought to a second position by rotary movements, and that the secondposition is maintained after rotary movements have been performed.

In an aspect of the present invention, the use according to claim 8 isparticularly advantageous when the object is a piece of hardware, suchas a card terminal which is to be operated by wheelchair users as wellas non-wheelchair users, where the position is changed by the two typesof users when using the hardware.

According to an aspect of the present invention, there is provided amethod as stated in claim 9.

In an embodiment, the attachment of the unit to the pipe is performed bywelding. In an embodiment, it is ensured by the welding that the pipe isdeformed elastically, and that the elastic deformation therebycontributes to a mechanical tension in the pipe.

In an embodiment, a mechanical tension in the pipe may be achieved byfirst applying a mechanical deformation of the pipe, thereby deformingthe pipe mechanically, and then attaching the unit so that a mechanicaltension is maintained after the application of the mechanicaldeformation has been discontinued.

According to an aspect of the present invention, there is provided amethod as stated in claim 10.

In an embodiment, the mechanical tension of the pipe may be changed byadding/removing one or more pairs of discs after the unit has beensecured to the pipe. This provides a simple manner in which themechanical tension in the pipe may be changed.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will be illustrated below by means ofexamples with a detailed description of preferred embodiments. Referenceis made to the figures in which:

FIG. 1 shows an embodiment of the invention, illustrating an uprightcomprising a rotatable link, a plate and a handle;

FIG. 2 illustrates individual parts incorporated in a link in anembodiment of the invention;

FIG. 3 illustrates individual parts incorporated in a link in anembodiment of the invention;

FIG. 4 shows an embodiment of the invention, illustrating a rotatablelink;

FIG. 5 a shows an embodiment of the invention, illustrating an uprightin a first position;

FIG. 5 b shows an embodiment of the invention, illustrating an uprightin a second position;

FIG. 6 a shows an embodiment of the invention, illustrating anotherrotatable link seen perpendicularly to the axis of rotation;

FIG. 6 b shows an embodiment of the invention, illustrating anotherrotatable link seen along the axis of rotation.

DETAILED DESCRIPTION

FIG. 1 shows the plate 11 on the link 1 as well as the strap 12 on theplate 11. See FIGS. 2-4 for the following description of the link 1. Thelink 1 is composed of: a through-going machine screw 5 havingtherearound two small cylinders 3 of a first diameter, two discs 8 ofsaid first diameter and a large cylinder 4 of a second diameter, saidsecond diameter being larger than the first diameter. A round hole ofapproximately the same diameter as the diameter of the screw 5 has beenmilled in both the two small cylinders 3, the two discs 8 and the largecylinder 4, said machine screw 5 extending through said hole. The largecylinder 4 is present on the longitudinal axis of the machine screw 5,approximately centrally thereon, and the two discs 8 and the smallcylinders 3 are arranged symmetrically around the large cylinder 4 suchthat a disc 8 is disposed between each of the small cylinders 3 and thelarge cylinder 4. One of the small cylinders 3 has threads for themachine screw 5 into which the machine screw 5 is screwed. The smallcylinders 3 and the large cylinder 4 are of compressed round steel andthe discs 8 are of brass.

The small cylinders 3, the discs 8 and the large cylinder 4 areassembled with the machine screw 5, see FIG. 2, and constitutes a unit71 as described above and indicated in FIG. 3. The above-mentioned unit71 is welded to a pipe stub 2, see FIG. 3. At one end the pipe stub 2 iscut at an angle of about 20° perpendicularly to the longitudinaldirection of the pipe stub 2, and two openings 6 are milled in thisinclined pipe edge. The two openings 6 in the inclined pipe edge formthe contact face for welding to the two small cylinders 3 of the unit71. The link 1 is shown assembled and mounted in FIG. 4. In the mountedstate, the pipe 2 is slightly elastically deformed by being expandedslightly in the direction of the machine screw 5. This gives rise to acompressive force of an elastic nature on the unit 71 from the pipe stub2 inwards toward the centre of the unit 71, see the arrows of force inFIG. 4. In the mounted link 1, it is only the large cylinder 4 which isrotatable (and partly the discs 8), whereas the two small cylinders 3are fixed and integrated with the pipe stub 2.

Welding of the plate 11 takes place on the large cylinder 4, see FIG. 1for a plate 11 welded on a link 1.

Mode of Operation

The pipe stub 2 applies a force to the unit 71. The force is generatedby the elastic deformation of the pipe stub 2 and acts along the axis ofthe link 1 from both sides of the pipe stub 2 inwards toward the centreof the unit 71.

The machine screw 5 is tightened firmly, which also produces compressiveforces that act inwards and compress the unit 71.

The total compressive force on the unit 71 causes a certain desirablesluggishness in the link 1, cf. the above-mentioned objects. Thesluggishness is partly brought about by applied forces from the pipestub 2, and the sluggishness is therefore partly dependent on thecompressive forces produced by the tightening of the machine screw 5.The machine screw 5 primarily has the effect of holding the parts of theunit 71 together rather than the effect of causing sluggishness in thelink 1. The frictional forces in the link 1 during rotation act interalia on the machine screw 5 in the direction of rotation, and thefrictional forces are assumed to be proportional to the force by whichthe screw 5 is tightened. If a very firmly tightened machine screw 5were used, this would cause great frictional forces that mightundesirably loosen the screw 5. The use of the compressive forces of thepipe stub 2 means that the screw 5 need not be tightened very much forthe given desired sluggishness. In this example, the screw 5 thus doesnot tend to loosen, which results in few post tightenings.

In this example, the discs 8 neutralize the frictional forces in thelink 1 in that the discs 8 are made of a softer material than thecylinder parts 3, 4.

In this example, the larger diameter of the large cylinder 4 relative tothe diameter of both the small cylinders 3 and the discs 8 makes itpossible to achieve a point on the link 1 for the welding of the plate11, which has been lifted clear of the partially concealed link 1 in thepipe opening, whereby the plate 11 may be rotated through the desiredrange in an angle of rotation of about 40°, see FIG. 5.

FIGS. 6 a and 6 b show an embodiment of a rotatable link 1, where, inaddition to two first cylinders 3 and the second cylinder 4, apertureddiscs 8 are provided in the rotatable link 1. Between a first cylinder 3and a second cylinder 4 and in the mentioned order and on each side ofthe second cylinder 4, there are: an apertured disc 82 of a firstmaterial and three apertured discs 81 of a second material. In thisexample the first material is brass, and the second material is steel.The second material may be spring steel. The second cylinder 4 and thetwo first cylinders 3 are made of sulphur-alloyed free-cutting steel inthis example. The pipe 2 is cut with two rim sections, and the upper rimsection is produced such that it comprises a step. One rim section ispart of a plane that forms an angle of about 20° with the horizontal,and the other rim section is part of a plane that forms an angle ofabout 60° with the horizontal. In this example, there is a hole in thewall of the pipe 2 in its lower area shown by a cantilever in profile inFIG. 6 b. A pawl may be inserted through this hole into the interior ofthe pipe 2, extending from the interior of the pipe wall inwards towardthe centre of the pipe 2. If the pipe 2 is mounted on a rod 13 having aslot, the pawl has the function of controlling the rotary movement inthat the pawl is present in the slot during the rotary movement. SeeFIG. 1 for an example of a slot in a rod 13.

FIGS. 1, 5 a and 5 b show examples of uprights 10 in embodiments of theinvention. FIG. 1 shows an upright 10 mounted on a horizontal face. Adescription of the upright 10 is given below, based on the mounted partof the upright 10 on the horizontal face. The upright 10 comprises afoot secured to an object, which is in turn secured to the rod 13. Theobject, shown here as a rod part, is secured in extension of the rod 13with its longitudinal direction different from the longitudinaldirection of the rod 13. The rod 13 is a circular hollow pipe and has aslot configured as a section in the rod 13 near the end of the rod 13,and the rod 13 has an outside diameter approximately equal to andsmaller than the inside diameter of the pipe 2. A pipe 2 is disposedaround and connected to the rod 13. A pawl (not shown) may be mounted inthe pipe 2, engaging the slot such that the pipe 2 is kept in itsvertical position in that the pawl is in contact with the edges of theslot, and such that, simultaneously with the vertical attachment, it ispossible to rotate the pipe about the longitudinal direction of the pipe2. The pipe 2 has a secured unit 71, and together they form a rotatablelink 1. A plate 11 is secured on the rotatable link 1, welded to therotatable link part of the unit 71. The plate has secured thereto ahandle 12 which a user may grip and move the plate 11 in a rotarymovement about the axis of the rotatable link part and/or about the axisalong the longitudinal direction of the pipe 2. An object (not shown),such as a piece of hardware, e.g. a card terminal, may be mounted orplaced on the plate. A screen capable of screening the hardware is shownmounted on the plate.

FIGS. 5 a and 5 b show an example of an upright 10. An object 14 ismounted on the upright 10. In FIG. 5 a, the upright 10 has a positionwhere the plate 11 has been rotated maximally in one direction about theaxis of the rotatable link part, such that it hits an upper part of therim of the pipe 2, said upper part forming a rim section. This rimsection is part of a plane having an inclination of about 20° with thehorizontal. In FIG. 5 b, the upright 10 has a position in which theplate 11 has been rotated maximally in the other direction about theaxis of the rotatable link part, such that it hits a lower part of therim of the pipe 2, said lower part forming a rim section. Whencontacting this rim section, the plate has an inclination of about 60°with the horizontal.

1. A rotatable link (1), comprising a pipe (2), two first objects (3)each having a bore, a second object (4) having a bore, and an attachmentmeans (5) extending through said bores and assembling, in said order, afirst object (3), the second object (4) and a first object (3) into aunit (71), characterised in that the two first objects (3) are securedto the pipe (2) on a part of the area of a rim (6) for the pipe (2),thereby providing a mechanical tension in the pipe (2) which istransferred as compressive forces in the longitudinal direction of theattachment means (5) to the second object (4), which forms a link partrotatable relative to the two first objects with an axis of rotationalong the longitudinal axis of the attachment means (5).
 2. A rotatablelink (1) according to claim 1, characterised by additionally comprisingone or more pairs of apertured discs (8), wherein it applies to eachpair of apertured discs (8) that the apertured discs (8) of a pair aredisposed on their respective sides of the second object (4) between thisand a first object (3) and with the attachment means (5) through thehole in the apertured discs (B).
 3. A rotatable link (1) according toclaim 2, characterised in that the number of pairs of apertured discs(8) is two or more, such as three or more, such as four or more.
 4. Arotatable link (1) according to claims 2-3, characterised in thatapertured discs (8) are made of a material selected from the followingsubstances: plastics and metal, such as brass and steel.
 5. A rotatableupright (10), comprising a rotatable link (1) according to any one ofthe preceding claims characterised in that a plate (11) is secured onthe rotatable link part.
 6. A rotatable upright (10) according to claim5, characterised by comprising a handle (12) secured to the plate (11).7. A rotatable upright (10) according to any one of claims 5-6,characterised by comprising a rod (13), said pipe (2) being mounted downalong said rod, with the longitudinal direction of the pipe (2) beingessentially in parallel with the longitudinal direction of the rod (13).8. Use of a rotatable upright (10) according to any one of claims 5-7for the positioning thereon of an object (14), such as a piece ofhardware.
 9. A method of manufacturing a rotatable link (1), comprisingassembling a unit (71) consisting of two first objects (3) each having abore, a second object (4) having a bore, and an attachment means (5) inthat the attachment means (5) is passed through said bores and, in saidorder, assembles a first object (3), the second object (4) and a firstobject (3), characterised by securing the unit (71) to a pipe (2) on apart of the area of a rim (6) of the pipe (2) with contact to the twofirst objects (3), thereby providing a mechanical tension in the pipe(2) which is transferred as compressive forces in the longitudinaldirection of the attachment means (5) to the second object (4), whichforms a link part rotatable relative to the two first objects with anaxis of rotation along the longitudinal axis of the attachment means(5).
 10. A method according to claim 9, characterised in that one ormore discs (8) of a pair are disposed on their respective sides of thesecond object (4) between this and a first object (3) and with theattachment means (5) through the hole in the apertured discs (8).